P0439 Ford Catalyst Heater Control Circuit Bank 2
Possible causes
– Catalyst Temperature Sensor harness is open or shorted
– Catalyst Temperature Sensor circuit poor electrical connection
– Faulty Catalyst Temperature Sensor
– Catalyst Temperature Sensor circuit poor electrical connection
– Faulty Catalyst Temperature Sensor
Symptoms
– Engine Light ON (or Service Engine Soon Warning Light)
P0439 Ford Description
The Engine Control Module (ECM) monitors the switching frequency ratio of heated oxygen sensors 1 (front O2 sensor) and heated oxygen sensors 2 (rear O2 sensor).
A three way catalyst converter (Manifold) with high oxygen storage capacity will indicate a low switching frequency of heated oxygen sensor 2. As oxygen storage capacity decreases, the heated oxygen sensor 2 switching frequency will increase.
When the frequency ratio of heated oxygen sensors 1 and 2 approaches a specified limit value, the three way catalyst malfunction is diagnosed.
Ford Vehicle:Ford Escape,Ford Focus Flexifuel,Ford Mustang,Ford Fusion,Ford Taurus,Ford F-Series,Ford Explorer,Ford C-Max,Ford Escape,Ford Edge,Ford Explorer,Ford Flex,Ford Expedition,Ford Transit Connect,Ford F1-50,Ford E-Series Wagon,Ford Super Duty,Ford Fusion Hybrid SE,Ford C-MAX Hybrid SEL,Ford C-MAX Energi,Ford Fusion Energi SE,Ford Fucos Electric,Ford E-Series Van,Ford E-Series Cutaway,Ford Super Duty Pick Up,Ford Chassis Cab,Ford F-650/F-750,Ford Stripped Chassis